1. (Field of the Invention)
The present invention generally relates to a disc player for reproducing information from an information carrier disc and, more particularly, to an automatic disc changer for the disc player for accommodating a plurality of information carrier discs and automatically setting them in a play position one by one to permit the disc player to reproduce information successively from the plural information carrier discs.
2. (Description of the Prior Art)
A compact disc player equipped with an automatic disc changer is currently available in the market. The disc changer incorporated in, for example, a portable CD (compact disc) radio cassette recorder available in the market is generally of a design in which a plurality of information carrier discs, that is, compact discs, are placed in a single, common plane and, therefore, includes a generally flat, intermittently rotatable rotary disc tray having a plurality of, for example, five, disc pockets defined on a circle depicted about the center of rotation of the rotary disc tray so that the compact discs can be successively brought to a play position as the rotary disc tray rotates.
The prior art disc changer referred to above will now be discussed in more detail with particular reference to FIGS. 14 to 16. FIG. 14 is an exploded view of the prior art disc changer and FIGS. 15 and 16 are cross-sectional representations taken along the lines A--A and B--B in FIG. 14, respectively.
The prior art disc changer shown in FIGS. 14 to 16 includes a generally square tray base 50 mounted on a panel chassis 51 within a changer or player housing (not shown) for movement between retracted and extended positions through a generally transversely elongated window 51a, having been guided by left and right guide ribs 51b which are fixedly mounted on the panel chassis 51 and slidingly engaged respectively in left and right guides 50a defined in left and right sides of the tray base 50. To prevent the panel chassis 51 from being floated from the panel chassis 51, left and right retainer pieces 52 are fixedly mounted on the panel chassis 51 so as to slidably overlay the left and right sides of the tray base 50, respectively. Each of the left and right retainer pieces 52 has a length so chosen that even when the tray base 50 is moved to the extended position in a direction indicated by the arrow G, respective portions of the left and right sides of the tray base 50 adjacent the rear side thereof which then remains within the player or changer housing will not float upwardly from the panel chassis 51.
The tray base 50 has a round recess defined therein so as to extend inwardly from an upper surface thereof for accommodating a rotary disc tray 53. The tray base 50 has a stud shaft 50e integrally formed therewith in coaxial relation with the center of the bottom of the round recess and also has a plurality of, for example, three roller pockets each delimited by a pair of downwardly extending walls 50d for accommodating a respective roller 54 as best shown in FIG. 15. The walls 50d of each pair have bearing holes 50i defined therein, and the corresponding roller 54 is rotatably accommodated within the roller pocket with a roller axle 54a rotatably received in the bearing holes 50i and fixed in position by a respective pawl 50c integral with the tray base 50. The rotary disc tray 53 has a center hole 53d and also has an undersurface formed with a circumferentially extending rib 53c coaxial with the center hole 53d. This rotary disc tray 53 is received within the round recess in the tray base 50 with the center hole 50d rotatably receiving the stud shaft 50e therein and with the circumferentially extending rib 53c resting on an outer peripheral surface 54b of each of the rollers 54 so that the rotary disc tray 53 can be turned in one of opposite directions, shown by the arrow-headed line C-D, about the stud shaft 50e integral with the tray base 50.
The rotary disc tray 53 is shown to have five round disc pockets 53a of a depth generally slightly smaller than the thickness of an information carrier disc, for example, a compact disc 61, defined on an upper surface thereof to occupy respective portions of a circle depicted about the center hole 53d. This rotary disc tray 53 has a generally U-shaped groove 53b cut radially inwardly from the outer periphery thereof so as to extend therefrom radially inwardly to a central portion of each disc pocket 53b. A size indicated by L1 in FIG. 15 is so chosen that none of the rollers 54 is viewable from the outside through the respective groove 53b.
A first drive motor 55 having a motor pulley 56 is mounted on the tray base 50 and is drivingly coupled with the rotary disc tray 53 for driving the latter about the stud shaft 50e. For this purpose, the rotary disc tray 53 has a geared wheel 53e integrally and coaxially formed with the undersurface thereof, which wheel 53e is with teeth 60a of a work gear 60 drivingly coupled with the motor pulley 56 through a speed reduction mechanism including an endless belt 57, a worm pulley 58 and a worm shaft 59. As best shown in FIG. 16, the work gear 60 is mounted on the worm shaft 59 under interference fit together with the worm pulley 58 with opposite ends of the worm shaft 59 rotatably received by spaced apart bearing pieces 50f integral with the tray base 50.
A second drive motor 62 is mounted on the panel chassis 51 and is drivingly coupled with the tray base 50. A rack gear 50g is rigidly secured to, or otherwise formed integrally with, the undersurface of the tray base 50 and is drivingly coupled with this second drive motor 62 through a speed reduction mechanism including a motor pulley 63, an endless belt 64, a pulley gear 65 and a drive gear 66 having teeth 66a meshed with the rack gear 50g so that the tray base 50 can be moved from the retracted position towards the extended position in a direction shown by the arrow G and from the extended position towards the retracted position in a direction shown by the arrow H depending on the direction of rotation of the second drive motor 62.
An optical pick-up unit 67 is mounted on the panel chassis 51 at a location within the player or changer housing and opposite to the elongated window 51a and includes a turntable 67a for the support from below of one of the compact discs 61 placed in the respective disc pockets 53a in the rotary disc tray 53. This optical pick-up unit 67 has stud shafts 67b protruding laterally outwardly therefrom in alignment with each other and pivotally received by respective brackets 51c, fixedly mounted on the panel chassis 51, so that the optical pick-up unit 67 can be pivoted up and down. A pin 67c carried by the optical pick-up unit 67 so as to protrude forwards rests slidingly on a cam portion 68a of an elevating gear 68 so that, when the elevating gear 68 is driven by a third drive motor 69 as will be described later, the pin 67c can be shifted upwardly or downwardly to cause the optical pick-up unit 67 to pivot in one of opposite directions shown by the arrow-headed line E and F about a common axis of the stud shafts 67b with the turntable 67c consequently lifted or lowered depending on the direction of rotation of the elevating gear 68. The third drive motor 69 is also mounted on the panel chassis 51 and has a motor pulley 70 drivingly coupled with the elevating gear 68 through a speed reduction mechanism including an endless belt 71 and a pulley gear 72.
The turntable 67a is cooperable with a clamper 73 rotatably received and retained in position within a hole 74a defined in a clamper support plate 74, which clamper 73 can pass through any one of the U-shaped grooves 53b in the rotary disc tray 53. This clamper support plate 74 is rigidly mounted on the panel chassis 51 with the clamper 73 positioned immediately above and in alignment with the turntable 67a. It is to be noted that the tray base 50 has a generally U-shaped cutout defined at 50h to accommodate the optical pick-up unit 67 when the tray base 50 is held at the retracted position having been moved in the direction H.
The prior art disc changer of the above described construction operates in the following manner. When the compact discs 61 are desired to be mounted on the rotary disc tray 53, a command necessary to move the tray base 50 to the extended position where at least two of the disc pockets 53a in the rotary disc tray 53 carried by the tray base 50 are exposed to the outside must be inputted to the disc changer in a manner known to those skilled in the art. In response to this command, the drive motor 62 is driven in one of opposite directions to drive the drive gear 66 through the speed reduction mechanism including the motor pulley 63, the endless belt 64 and the pulley gear 65 and, therefore, the tray base 50 is moved from the retracted position towards the extended position in the direction G by meshed engagement between the teeth 66a of the drive gear 66 with the rack gear 50g integral with the tray base 50. The drive motor 62 once driven is brought to a halt in response to arrival of the tray base 50 at the extended position. It is to be noted that, even when the tray base 50 is moved to the extended position, the tray base 50 does not "slouch" because, as hereinbefore described, the left and right retainer pieces 52 retain the respective portions of the left and right sides of the tray base 50 adjacent the rear side thereof which then remains within the player or changer housing.
With the tray base 50 brought to the extended position, two of the disc pockets 53a are simultaneously exposed to the outside of the disc changer and, hence, set at a loading position and, therefore, two compact discs 61 can be simultaneously placed within the respective disc pockets 53a. After the placement of the two compact discs 61 in the respective disc pockets 53a, and where additional compact discs 61 are desired to be placed in the remaining disc pockets 53a then concealed within the player or changer housing, a command necessary to drive the drive motor 55 should be inputted to the disc changer. Once this command is inputted, the drive motor 55 is driven for a preset length of time to drive the rotary disc tray 53 about the stud shaft 50e in one of the opposite directions C and D through the speed reduction mechanism, including the motor pulley 56, the endless belt 57, the worm pulley 58, the worm shaft 59 and the worm gear 60 having the teeth 60a meshed with the geared wheel 53 integral with the rotary disc tray 53, thereby bringing the other two of the remaining disc pockets 53a to the outside of the player or changer housing through the window 51a and, hence, to the loading position. Since the drive motor 55 is brought to a halt in response to turning of the rotary disc tray 53 through the predetermined angular distance, the additional two compact discs 61 can be placed in the corresponding disc pockets 53a then held at the loading position.
Thus, the rotary disc tray 53 is turned intermittently a predetermined angular distance required for each two of the disc pockets 53a to be brought to the loading position outside the player or changer housing. By repeating this procedure, all of the disc pockets 53a in the rotary disc 53 can have the corresponding compact discs 61 placed therein.
Subsequent depression of a "PLAY" button (not shown) results in generation of a start command with which the various electric component parts are sequentially operated. Namely, the drive motor 62 is reversed to rotate in the opposite direction to move the tray base 50 from the extended position towards the retracted position in the direction H. In response to arrival of the tray base 50 at the retracted position, the drive motor 55 is again driven to turn the rotary disc tray 53 in one of the opposite directions C and D about the stud shaft 50e to bring one of the disc pockets 53a and, hence, the compact discs 61 accommodated therein, to a play position immediately beneath the clamper 73. In response to arrival of one of the compact discs 62 at the play position, not only is the drive motor 55 brought to a halt, but the drive motor 69 is driven to drive the elevating gear 68 through the speed reduction mechanism including the motor pulley 70, the belt 71 and the pulley gear 72, causing the optical pick-up unit 67 to pivot upwardly about the common axis of the stud shafts 67b in the direction E. As a result of this, the turntable 67a is lifted until an inner peripheral portions of the associated compact disc 61 around a center hole thereof is clamped between the turntable 67a and the clamper 73. Shortly thereafter, in a manner known to those skilled in the art, the compact disc 61 at the play position is driven at a high speed and music recorded on the compact disc 61 is reproduced.
After the music on the compact disc 61 has been completely played, the drive motor 69 is reversed to rotate in such a direction required to pivot the optical pick-up unit 67 in the direction F with the turntable 67a consequently lowered while allowing the compact disc 61 to be seated within the disc pocket 53a, followed by the drive of the drive motor 55 to turn the rotary disc tray 53 to thereby bring the next succeeding compact disc 61 to the play position. In response to the arrival of the next succeeding compact disc 61 at the play position, the optical pick-up unit 67 is again pivoted in the direction E in a similar manner as hereinbefore described to allow an inner peripheral portion of the next succeeding compact disc 61 to be clamped between the turntable 67a and the clamper 73 in readiness for reproduction of music from such next succeeding compact disc 61.
Where the compact discs 61 within the corresponding disc pockets 53a in the rotary disc tray 53 are desired to be replaced with other compact discs or removed from the disc pockets 53a, the drive motor 69 must be driven to pivot the optical pick-up unit 67 in the direction F to lower the turntable 67a, followed by drive of the drive motor 62 to move the tray base 50 from the retracted position towards the extended position in the direction G. At the time the tray base 50 is brought to the extended position, two of the compact discs 61 are returned to the loading position and, therefore, can be removed from the associated disc pockets 53a. If desired, two different compact discs may be placed in the disc pockets 53a in the case of replacement. Complete removal of the five compact discs 61 can be accomplished by intermittently turning the rotary disc tray 53 by driving the drive motor 55 in response to a required command.
On the other hand, where some of the compact discs 61 within the corresponding disc pockets 53a in the rotary disc tray 53 are desired to be removed or replaced, a requisite command should be inputted to drive the drive motor 62 so that the tray base 50 can be moved from the retracted position towards the extended position in the direction G. Thereafter, the drive motor 55 should be driven in response to another requisite command to turn the rotary disc tray 53 until such some of the compact discs 61 desired to be removed or replaced are brought back to the loading position, and then they can be manually removed from the corresponding disc pockets 53a or replaced with different compact discs 61.
The prior disc changer of the type shown in and described with reference to FIGS. 14 to 16 has some problems. Specifically, since the prior art disc changer makes use of the generally flat, intermittently rotatable rotary disc tray having the plural disc pockets defined in a common plane, the rotary disc tray occupies a relatively large quantity of space, rendering the disc changer as a whole to be bulky in structure.
Also, in order for the disc changer to have a capability of allowing some of the compact discs to be removed or replaced while one of them is still held at the play position, the prior art disc changer requires three separate drive systems including the respective drive motors, rendering the disc changer as a whole to be complicated in structure and expensive with the necessity of use of a substantially increased number of component parts.